Display screen or portion thereof with transitional graphical user interface



FIG. 1 is a front view of a display screen or portion thereof with transitional graphical user interface showing a first image in a first sequence according to the claimed design;

FIG. 2 is a front view showing a second image in the first sequence according to the claimed design;

FIG. 3 is a front view showing a first image in a second sequence according to the claimed design;

FIG. 4 is a front view showing a second image in the second sequence according to the claimed design;

FIG. 5 is a front view showing a first image in a third sequence according to the claimed design;

FIG. 6 is a front view showing a second image in the third sequence according to the claimed design;

FIG. 7 is a front view showing a first image in a fourth sequence according to the claimed design; and,

FIG. 8 is a front view showing a second image in the fourth sequence according to the claimed design.

The appearance of the image transitions sequentially between the images shown in FIGS. 1-2, FIGS. 3-4, FIGS. 5-6, and FIG. 7. The process or period in which one image transitions to another image forms no part of the claimed design.

The shading depicts a contrast in appearance.

The two outermost broken lines and the large, lower broken line circle illustrate an electronic device, which is the environment of the design, and form no part of the claimed design. The dot-dot-dash broken lines illustrate a symbolic break in vertical dimension. The appearance of any portion of the graphical user interface between the break lines forms no part of the claimed design. The remaining broken lines illustrate portions of the display screen and portions of the graphical user interface that form no part of the claimed design. 

CLAIM The ornamental design for a display screen or portion thereof with transitional graphical user interface, as shown and described. 